Transparent sheet and process of manufacture



Patented Jan. 3,- 1 933 l,8fl3,172

EDOUARD M. KRA'IZ, OF CHICAGQ, ILLINOIS,

ASSETS-NOR. TO MARfiENE PRODUCTS 00.,

OF CHICAGO, ILLINOIS, A CGFRPORATIGN OE ILLINOIS TRANSPARENT SHE-ET AND PROCESS OF MANUFACTURE No Drawing.

This invention relates to a process for the manufacture of transparent sheets of gelatine composition, more particularly thin, clear, transparent and flexible sheets, adapted for use as candy box wrappers, lower wraps, etc.

Sheets made from gelatine alone are hard and brittle when cold, and soft and sticky when hot. Such sheets are not, therefore, suitable for the purposes intended. .Vhen glycerine is used to soften the gelatine and render the sheets flexible, the sheets are still subject to the effect of climatic conditions. When the weather is not too hot or humid, the sheets are fairly satisfactory; but in hot, damp weather, they become soft and sticky and in dry cold weather they crumble easily.

lhis invention has for one of its objects an improvement in the process of manufacture of transparent sheets over the process using gelatine alone, or gelatine and glycerine.

A further object is an improvement in the composition of gelatine sheets to render them unaffected by changes in climatic conditions, such as heat, cold, dryness and dampness.

A further object is an improvement in the qualities of a gelatine sheet, such as clearness, transparency, toughness and flexibility.

A further object is a process of manufacture of gelatine sheets in various colors, or plain white.

Other and further important objects of the invention will be apparent from the disclosures in the following description, which sets forth the preferred form of my invention.

I have found that the use with gelatine of a suitable sulphonated oil gives the required degree of softening effect and, at the same time, the sheets made from this composition are not afiected by climatic conditions. I have further found that a small quantity of acid, such a phosphoric, aids in obtaining a clear sheet, and that the natural yellow cast of the sheet may be counteracted to give a white shade by the use of dyestuffs, or the sheet may be dyed to any depth of color.

The proportion of sulphonated oil to gelatine may be varied over a considerable range, depending upon the qualities desired in the sheet.

Application filed February 21, 1925.

Serial No. 10,982.

Ordinarily the percentage of sulphonated oil will be within the limits of 5 to Below 5% the resulting sheets would be too hard and brittle, and above 60% they would be too soft and lack coherence.

more satisfactory range would be from 15 to 40% sulphonated oil. The phosphoric acid may be varied from 0.-lto 1% by weight. The sulphonated oil, preferably castor oil, may be sulphonated so as to contain between i and 10% by weight of sulphonic acid radical.

I prefer to use a composition containing about 25% of 8% sulphonated castor oil of which 25% is water. My preferred proportions are as follows:

By weight: 8 parts glue, 1 part 8% sulphonated oil, 0.036 part 50% orthophosphoric acid.

0 in my process of manufacture, the glue is iii-st soaked in four times its weight of cold water for at least six (6) hours, then melted at 115 F. To this is added the phos phoric acid previously diluted 200 to 1. After adding the acid, the bath is agitated thoroughly. In a separate vessel the 8% sulphonated c-astor oil is diluted with ten (10) parts of water at 110 F. and mixed thoroughly, and then added to the gelatine solution with agitation. The temperature must be maintained between 100-120 F. To counteract the yellow cast in the natural sheet, 0.02 parts of alizarine sapphirol or about 0.5% by weight of the dry gelatine composition may be added to the solution. To give a color to the sheet more dye may be added, or others to give dilferent colors. Tanning solutions, such as formaldehyde, maybe used if desired. in quantities of 0.066 to 0.26 parts of 40% formaldehyde solution. One of the effects of a tanning agent such as formaldehyde, is to reduce the tendency for two portions of a sheet of my material to adhere to each other when moist. On the other hand tanning reduces the fleXibi ity and toughness of the sheet and may, therefore, not always be desirable. The bath is now diluted with soft water at 100 F. to the viscosity required to give the desired sheet. Preferably, however, in routine worl: all of the water re-,

quired' for dilution is added tothe glue at the time the latter is melted. The sheet is then formed on an endless belt that picks up a film of the solution in passing between rolls. The belt passes through a chill box to set the sheet and over suction boxes or drums to pull the belt forward. The sheet is finally dried by hanging it in festoons over racks.

The gelatine used should be glue from the first boiling of calf skin stock, on account of the strength and purity of glue required. If desired the glue can be filtered after dilution. The lue should be free from preservatives, especially zinc sulphate.

The sulph onated oil must be free from alkalies and acids. It should be a thoroughly Washed oil, neutralized after sulphonation by sodium 01' potassium hydroxide, and even with a soda neutralized. oil a sulphonation as low as 3% is not ordinarily satisfactory. An ammonia neutralized oil is not satisfactory as it produces cloudiness in the sheet, probably due to evolution of ammonia. The oil should be neutral to methyl orange; if on thealkaline side, the sheet made therefrom will have a milky appearance.

Further, the oil should be free from impurities, especially stearin. On this account, not all sulphonatedoils are suitable. Sulphonated castor oil has proved to be the one most satisfactory.

I am aware that numerous details of the process may be Varied through a wide range without departing from the spirit of this invention, and do not desire limiting the patent granted otherwise than as necessitated by the prior art.

I claim as my invention: I

1. A gelatine sheet comprising 'gelatine, orthophosphoric acid, and sulphonated castor. oil.

2-. A gelatine sheet comprising to 94% gelatine, 5 to of 4 to 10% sulphonated castor oil, 1% or less of orthophosphoric acid, and a dyestufl.

3. A gelatine sheet comprising 60 to 8 1% gelatine, 15 to l0% of 4 to 10% sulphonated castor oil, 1% or less of orthophosphoric acid, and a dyestufl'.

1. A gelatine sheet compris'ng about 74% gelatine, 25% of 8% sulphonated castor oil, 0.5% orthophosphoric acid, and 0.5% all:

'zarine sapphirol.

5. A gelatine sheet comprising about? 0% gelatine, 25% of 8% sulphonated castor oil, 0.5% ortl'iophosphoric acid, 0.5% alizarine sapphirol and 4% of 40% formaldehyde.-

6. A gelatine sheet comprising 15 to 10% of 4 to '10% sulphonated castor oil, 60 to gelatine, 1% or less of orthophosphcric acid, 1% or less of 'dyestulf and formaldehyde. 1 p

7. A clear, transparent, flexible sheet comprising gelatine, sulphonated castor oil and orthophosphoric acid, the amount of gelatine Qto 8% of 4r0%' being in excess of the sulphonated castor oil and orthophosphoric acid.

8. A clear, transparent, flexible sheet comprising approximately three parts of gelatine, one part of sulphonated castor oil and a small amount of orthophosphoric acid.

9. clear, transparent, flexible sheet'comprising approximately three parts of gelatine, one part of sulphonated castor oil and about .03 parts of orthophosphoric acid. 7

10. A clear, transparent, flexible sheet compris'ng approximately three parts of gelatine, one part of l to 10% sulphonated castor oil and about .03 parts of 50% orthophosphoric acid.

In testimony whereof I have hereunto. subscribed my name. I

" E OUABD M. gna'rz. 

